The goal of Zynaxis is commercialization of diagnostic and therapeutic products derived from proprietary cell tracking molecules (Zyn- Linkers(TM)). Specifically, a biologically active Zyn-Linker(TM) molecule conjugated to heparin (PKH 136) during Phase I of the study merits further evaluation for the local prevention of thrombosis and restenosis in coronary vessels subjected to angioplasty, a procedure performed in 400,000 U.S. patients per year. If effective, such a molecule would substantially reduce the number of repeat procedures following angioplasty and save approximately 2 billion dollars annually. The overall goals of Phase II are to use information obtained in Phase I to develop Zyn-Linker/heparin conjugates which possesses local antithrombotic and antirestenosis activity and to identify a suitable candidate for Phase III studies including pathology/toxicology as well as Phase I and II clinical testing in normal and angioplasty patients, respectively. Specific aims of Phase II include l) resynthesis, purification (>90%), and development of more efficient synthetic chemistry for the Zyn-Linker/heparin conjugate PKH 136; 2) testing PKH 136 to determine its local antithrombitic/antirestenosis efficacy in animal models; and 3) if necessary, synthesis and testing of a releasable Zyn- Linker/heparin conjugate analog in animal models. PROPOSED COMMERCIAL APPLICATION: The goal of Phase II studies is to develop Zyn-Linker/heparin conjugates which have local antirestenotic and antithrombotic activity. Since angioplasty is performed in approximately 400,000 U.S. patients per year, the cost savings of a local antirestenotic/antithrombotic drug in terms of repeat procedures following restenosis is estimated to be between 2 to 4 billion dollars annually. The estimated commercial market for such an agent is approximately 200 to 400 million dollars annually.